when two lines cross like this, sum of measures of opposite angles is 180.
this means that:
measure angle AEC + measure angle BED = 180
4x-40 + x+50 = 180
5x +10 = 180
5x = 170
x = 34
therefore:
measure angle AEC = 4x-40 = 4(34)-40 = 96
measure angle BED = x+50 = 34+50 = 84
